The present invention relates generally to methods and systems for brazing materials, and more particularly to an improved brazing system for titanium aluminide.
Titanium aluminide is an intermetallic compound of relatively recent development having good high temperature (to about 2000.degree. F.) properties and is a candidate for high temperature applications such as in turbine rotors and blades and other jet engine parts. Because of its high strength to weight ratio, titanium aluminide in either of its phases (alpha Ti.sub.3 Al or gamma TiAl) or in alloy system(s) with other metal(s) may be used to fabricate parts having substantially lighter weight than parts fabricated from nickel base superalloys. Although titanium aluminide is brittle at room temperature and is considered generally hard to fabricate, recent advances in powder metallurgy and rapid solidification technology have allowed expanded use of titanium aluminide materials in the fabrication of quality parts. Most applications of titanium aluminide material, however, require that it be welded, brazed or otherwise joined to a similar material or to other high temperature materials such as Hastelloy X sheet or honeycomb, Inconel-718, titanium alloys, or Incology-907. Existing brazing methods and materials have proved unsatisfactory in many respects for providing reliable joints for titanium aluminide materials and therefore a need exists for a reliable method for brazing this material.
The invention describes a method for brazing titanium aluminide using a filler material which does not melt at a desired brazing temperature when not in contact with the titanium aluminide base material but when placed in contact with the titanium aluminide material activates the surface thereof to form with titanium a eutectic composition which melts at the desired brazing temperature.
It is therefore an object of the invention to provide a brazing system for titanium aluminide.
It is a further object of the invention to provide a method for brazing titanium aluminide.
These and other objects of the invention will become apparent as the detailed description of representative embodiments proceeds.